Comparative T-S plots between SES CTD (LHS) and ROMS (RHS) profiles within four East Antarctic polynyas.

<p>a, b) Cape Darnley (Jan–Nov), c, d) Mackenzie Bay (Feb–Sept), e, f) Prydz Bay (Mar–Nov) and g, h) West Ice Shelf (May–Oct). Profiles are coloured by day of year to show the seasonal progression, where summer is deep red leading into dark blue during the middle of winter. Seal data include all observations at all depths extracted from within a surface heat flux contour defining the most active region of each polynya (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184536#pone.0184536.s008" target="_blank">S2 Appendix</a>). The ROMS output displays a profile from every grid cell within the centroid, at fortnightly intervals. The approximate freezing point of water (-1.85°C) and the potential density curve representing AABW (σ₂ = 37.16 kg m^-3) are shown in black.